A teacher, while explaining air characteristics, took a cycle tube, pumped air into it and asked the students to press the tightly filled tube. Which one of the following is most appropriately explained by this experiment?

Correct option is D

Introduction
When air is pumped into a cycle tube, it fills the volume. When the students press the tightly filled tube, they are able to decrease its volume slightly. This observation demonstrates the characteristic of a gas, in this case, air, being able to be compressed into a smaller volume under pressure. The ability to reduce the tube's size by pressing it directly shows that air is compressible.
Information Booster
· Experiment: Pumping air into a tube and then pressing the filled tube.
· Observation: The tightly filled tube can be slightly deformed or reduced in volume by applying pressure.
· Principle: This is a direct physical demonstration of the property of a gas, where the particles are far apart and can be easily forced closer together.
· Scientific Concept: Air is compressible because it is a mixture of gases.
· Contrast: Liquids and solids are considered nearly incompressible.
Additional Points
· Cycle tube is expandable: While true (it expands to hold the air), the core concept demonstrated by pressing the filled tube is the compressibility of the air, not the tube material.
· Tube may burst when excess air is filled: This relates to the tensile strength of the tube material and the pressure limit, not the inherent characteristic of air demonstrated by simple pressing.
· Air is visible: Air is generally invisible; this experiment does not demonstrate its visibility.